Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Ca$	Calcium	element	1 - 2		constituent element	main
	$Mg$	Magnesium	element	2 - 4		constituent element	main
	$Fe^{2+}$	Iron(II) cation	element	0 - 2		constituent element	main
	$Fe^{3+}$	Iron(III) cation	element	0 - 2		constituent element	main
	$Al$	Aluminium	element	1 - 3		constituent element	main
	$Ti$	Titanium	element	0 - 1		constituent element	main
	$Si$	Silicon	element	3 - 5		constituent element	main
	$O$	Oxygen	element	20		constituent element	main

Composition comments

Proportions are very various. Common impurities: K, Na, Mn

Oxides

Formula	$K_{2}O$	$Na_{2}O$	$CaO$	$MgO$	$TiO_{2}$	$Al_{2}O_{3}$	$FeO$	$Fe_{2}O_{3}$	$SiO_{2}$
Mass fraction (%)

Strunz

Class

silicates (09)

Division

inosilicate (09.D)

Family

with 4-periodic single chains, Si4O12 (09.DH)

Code

09.DH.45

Dana

Major class

silicates (VIII)

Class

inosilicate chains with side branches or loops (69)

Type

with P>2 (69.02)

Group

Aenigmatite and related species (Aenigmatite subgroup) (69.02.01a)

Code

69.02.01a.05

Phase type

crystalline

Crystal system

triclinic

Crystal class

pinacoidal

Crystal class symbol

-1 (Ci)

Crystal spacegroup

P1

Refringence type

biaxial

Refringence sign

positive

Birefringence

0.0350

Refraction index $n_{\alpha}$

1.795 - 1.81

Refraction index $n_{\beta}$

1.806 - 1.825

Refraction index $n_{\gamma}$

1.83 - 1.845

Dispersion V

r > v extreme

Pure color

brown

Color

brown, black

Diaphaneity

translucent to opaque

Luster

submetallic

Links

• Webmineral database
• Mindat
• Handbook of Mineralogy (Min. Soc. Am)